The present invention relates to a composition of matter and more particularly it relates to a substrate of aluminum, e.g., metal or aluminum alloy on the surface of which is bonded a film of diamond. The present invention also includes within its scope a process for bonding diamond onto such a substrate.
Diamond coatings of aluminum alloys are attractive for several mechanical and electronic applications. The mechanical advantages of diamond surface coatings include for example improve wear or abrasion resistance and in some instances erosion resistance. The electronic applications of these diamond coated bodies rely on the excellent thermal conductivity and high electrical resistance of the diamond. The production of these hybrid systems exhibiting good bonding, however requires good processes.
The critical technological issue that currently frustrates the production of such diamond films on aluminum substrate is that good quality diamond films can only be grown on substrates that are heated between 800.degree. and 1000.degree. C. Since aluminum alloys melt at about 600.degree.-700.degree. C., aluminum alloy substrates cannot be employed to support the growth of good quality diamond films. The process to apply diamond films to aluminum or aluminum alloys must involve means of growing the film at high temperature and then providing a means for bonding the film to the aluminum substrate by a method that yields a good metallurgical bond.
Diamond films can be grown on silicon substrates. The growth can be either by microwave or plasma means but a critical parameter for good film growth is the temperature of the substrate upon which the film is to be deposited. Generally speaking, control of the substrate temperature in a range of 800.degree.-1000.degree. C. is needed to ensure high quality diamond films. Films that are grown under these conditions can be stripped of their silicon substrates by chemical etching and subsequently applied to coat other materials.